This invention relates to a liniment and method of treating horses for bowed tendons.
Like any other animal, horses suffer soft tissue injuries. One type soft tissue injury is called a bowed tendon in which one of the major leg tendons is injured. Three common responses to tendon injuries are strain, contracture of the tendon and adhesion of the tendon to its sheath. A rare response to a tendon injury is rupture of the tendon. A bowed tendon heals by proliferation of the tissue around it, much like a bony callus forms. When the tendon does heal, it often adheres to things nearby. This abnormal adhesion of the tendon to adjacent tissues is the reason why the bowed tendon is a major problem which lasts so long.
The three major tendons in a horse's leg are the interosseus medius tendon or the suspensory ligament, the deep flexor tendon and the superficial flexor tendon. These tendons act as shock absorbers as the horse's hoof strikes the ground. These tendons normally are elastic enough to be effective, but abnormal stress causes collagen fibers and blood vessels within the tendons to tear. Most bowed tendons in race horses involve damage to the superficial flexor tendon.
In a bowed tendon, blood from ruptured vessels causes swelling along the back of the injured leg, thus the term "bowed." Symptoms range from minor soreness to lameness. Swelling is apparent in moderate to severe cases. Although horses are normally very fast healing animals, a bowed tendon does not normally heal easily because there is insufficient blood circulation into the damaged tendon. As the tendon heals, scar tissue forms adhering the tendon to the tendon sheath.
The standard treatment for a bowed tendon has been to fire the injured leg after the swelling has gone down, blistering the leg several times over the firing and then give the horse rest for at least one year. A great deal of time, effort and money is always tied up in a well trained race horse. Thus, the prospect of watching one's investment be idle for a year is unsatisfactory. Even worse, the future of world class athletes who have sat out for a year is dismal because very few ever again return to their prior performance level.
A more complete discussion of bowed tendons is found in an article entitled "Treating Tendon Trouble", The Blood-Horse of June 25, 1988, pp 3570-71. Disclosures of interest are in U.S. Pat. No. 4,353,896 and a book entitled DMSO, The True Story of a Remarkable Pain-Killing Drug by Barry Thrasis.
Dimethylsulfoxide (DMSO) is a highly polar, stable, hygroscopic organic liquid with exceptional solvent properties. DMSO easily penetrates the dermal barrier of animals and has been tested for use in certain types of topical preparations, e.g. see "Topical Pharmacology and Toxicology of Dimethyl Sulfoxide--Part I," Journal of the American Medical Association, Volume 193, No. 10, p 796 and literature cited therein. DMSO is a well known carrier for various topically applied medications and has the peculiar property of imparting a garlic or oyster taste in the mouth of the recipient within seconds of topical application.
In the course of this invention, applicant has tried DMSO alone on bowed tendons in horses. DMSO alone tends to reduce inflammation in the tendon, reduce swelling and give general relief to the horse but does not set the tendon, i.e. cause the tendon to harden and return to its pre-damaged condition. A horse treated with DMSO alone shows general improvement in a short period of time but reinjures the tendon almost immediately when put back to training or racing.